package api

import (
	"net/http"
	"strconv"
	"strings"

	"github.com/gin-gonic/gin"

	"fileshare/internal/response"
	"fileshare/internal/settings"
)

// fileSizeUnits 文件大小单位（对齐参考 FILE_SIZE_UNITS）。
var fileSizeUnits = map[string]int64{"KB": 1024, "MB": 1024 * 1024, "GB": 1024 * 1024 * 1024}

// saveTimeUnits 保存时间单位（秒）。
var saveTimeUnits = map[string]int64{"second": 1, "minute": 60, "hour": 3600, "day": 86400}

// expireStyleOptions 可用过期方式（用于 setup 表单校验）。
var expireStyleOptions = []string{"day", "hour", "minute", "forever", "count"}

// setupFormValue 取表单/JSON 字符串值。
func setupFormValue(data map[string]any, key, def string) string {
	v, ok := data[key]
	if !ok || v == nil {
		return def
	}
	if s, ok := v.(string); ok {
		return s
	}
	return strings.TrimSpace(strconv.FormatFloat(toAnyFloat(v), 'f', -1, 64))
}

func toAnyFloat(v any) float64 {
	switch n := v.(type) {
	case float64:
		return n
	case int:
		return float64(n)
	case int64:
		return float64(n)
	}
	return 0
}

// registerSetup 注册初始化向导（未初始化时唯一可用入口，白名单 /setup）。
func registerSetup(r *gin.Engine, d *Deps) {
	r.GET("/setup", func(c *gin.Context) {
		if d.Mgr.IsInitialized() {
			c.Redirect(http.StatusSeeOther, "/")
			return
		}
		c.Data(http.StatusOK, "text/html; charset=utf-8", []byte(buildSetupPage("")))
	})
	r.POST("/setup", func(c *gin.Context) {
		if d.Mgr.IsInitialized() {
			c.Redirect(http.StatusSeeOther, "/")
			return
		}
		d.setupSubmit(c)
	})
}

// setupSubmit 处理初始化提交（对齐参考 setup_submit + parse_setup_options）。
func (d *Deps) setupSubmit(c *gin.Context) {
	// 兼容 JSON 与表单
	data := map[string]any{}
	if strings.Contains(c.GetHeader("Content-Type"), "application/json") {
		if err := c.ShouldBindJSON(&data); err != nil {
			c.Data(http.StatusBadRequest, "text/html; charset=utf-8", []byte(buildSetupPage("请求体格式错误")))
			return
		}
	} else if err := c.Request.ParseForm(); err != nil {
		c.Data(http.StatusBadRequest, "text/html; charset=utf-8", []byte(buildSetupPage("请求体格式错误")))
		return
	} else {
		// 多值字段（如多个 expireStyle 复选框）保留完整列表，单值取首项
		for k, v := range c.Request.PostForm {
			switch {
			case len(v) == 1:
				data[k] = v[0]
			case len(v) > 1:
				data[k] = v
			}
		}
	}

	adminPassword := setupFormValue(data, "admin_password", "")
	confirmPassword := setupFormValue(data, "confirm_password", "")
	siteName := setupFormValue(data, "site_name", "")

	if adminPassword == "" || len(adminPassword) < 8 {
		c.Data(http.StatusBadRequest, "text/html; charset=utf-8", []byte(buildSetupPage("管理员密码至少 8 位")))
		return
	}
	if adminPassword != confirmPassword {
		c.Data(http.StatusBadRequest, "text/html; charset=utf-8", []byte(buildSetupPage("两次输入的管理员密码不一致")))
		return
	}
	patch, errMsg := parseSetupOptions(data)
	if errMsg != "" {
		c.Data(http.StatusBadRequest, "text/html; charset=utf-8", []byte(buildSetupPage(errMsg)))
		return
	}
	patch["site_name"] = firstNonEmpty(siteName, "文件快传")
	patch["admin_token"] = settings.HashPassword(adminPassword)
	patch["jwt_secret"] = settings.GenerateJWTSecret()

	ctx := c.Request.Context()
	if err := d.Mgr.UpdateKV(ctx, patch); err != nil {
		c.Data(http.StatusInternalServerError, "text/html; charset=utf-8", []byte(buildSetupPage("初始化失败: "+err.Error())))
		return
	}
	if err := d.Mgr.Reload(ctx); err != nil {
		c.Data(http.StatusInternalServerError, "text/html; charset=utf-8", []byte(buildSetupPage("配置重载失败: "+err.Error())))
		return
	}
	d.syncRateRules()
	// JSON 请求返回 JSON；表单返回成功页
	if strings.Contains(c.GetHeader("Accept"), "application/json") ||
		strings.Contains(c.GetHeader("Content-Type"), "application/json") {
		response.OK(c, gin.H{"ok": true, "admin": "/#/admin"})
		return
	}
	c.Data(http.StatusOK, "text/html; charset=utf-8", []byte(buildSetupSuccessPage()))
}

// parseSetupOptions 解析并校验初始化选项（对齐参考 parse_setup_options）。
func parseSetupOptions(data map[string]any) (map[string]any, string) {
	out := map[string]any{}

	// 文件大小限制
	unit := strings.ToUpper(setupFormValue(data, "upload_size_unit", "MB"))
	if _, ok := fileSizeUnits[unit]; !ok {
		return nil, "文件大小单位不正确"
	}
	sizeVal, err := strconv.Atoi(setupFormValue(data, "upload_size_value", "10"))
	if err != nil || sizeVal < 1 {
		return nil, "文件大小限制必须是正整数"
	}
	out["uploadSize"] = int64(sizeVal) * fileSizeUnits[unit]

	// 最长保存时间
	saveUnit := strings.ToLower(setupFormValue(data, "save_time_unit", "day"))
	if _, ok := saveTimeUnits[saveUnit]; !ok {
		return nil, "最长保存时间单位不正确"
	}
	saveVal, err := strconv.Atoi(setupFormValue(data, "save_time_value", "0"))
	if err != nil || saveVal < 0 {
		return nil, "最长保存时间必须是非负整数"
	}
	out["max_save_seconds"] = int64(saveVal) * saveTimeUnits[saveUnit]

	// 过期方式白名单
	var styles []string
	if raw, ok := data["expireStyle"]; ok {
		switch v := raw.(type) {
		case []any:
			for _, item := range v {
				if s, ok := item.(string); ok {
					styles = append(styles, s)
				}
			}
		case []string:
			styles = v
		case string:
			for _, s := range strings.Split(v, ",") {
				styles = append(styles, strings.TrimSpace(s))
			}
		}
	}
	valid := map[string]bool{}
	var finalStyles []string
	for _, s := range styles {
		s = strings.TrimSpace(s)
		if s == "" || valid[s] {
			continue
		}
		for _, opt := range expireStyleOptions {
			if opt == s {
				valid[s] = true
				finalStyles = append(finalStyles, s)
				break
			}
		}
	}
	if len(finalStyles) == 0 {
		return nil, "至少需要选择一种过期方式"
	}
	out["expireStyle"] = finalStyles

	// 取件码类型
	codeType := setupFormValue(data, "code_generate_type", "secret")
	if codeType != "number" && codeType != "secret" {
		return nil, "提取码类型不正确"
	}
	out["code_generate_type"] = codeType

	// 频率限制
	for _, item := range []struct{ key, def string }{
		{"errorCount", "10"}, {"errorMinute", "1"},
		{"loginCount", "5"}, {"loginMinute", "15"},
		{"uploadCount", "10"}, {"uploadMinute", "1"},
	} {
		n, err := strconv.Atoi(setupFormValue(data, item.key, item.def))
		if err != nil || n < 1 {
			return nil, item.key + " 必须是正整数"
		}
		out[item.key] = n
	}

	// 布尔开关
	out["openUpload"] = boolToInt(parseSetupBool(data, "openUpload", true))
	out["enableChunk"] = boolToInt(parseSetupBool(data, "enableChunk", false))

	// 允许文件类型
	allowed := setupFormValue(data, "allowed_file_types", "*")
	var types []string
	for _, item := range strings.Split(allowed, ",") {
		if item = strings.TrimSpace(item); item != "" {
			types = append(types, item)
		}
	}
	if len(types) == 0 {
		types = []string{"*"}
	}
	out["allowed_file_types"] = types
	return out, ""
}

// parseSetupBool 解析表单布尔（缺省 default；"1"/"true"/"on"/"yes" 为真）。
func parseSetupBool(data map[string]any, key string, def bool) bool {
	v, ok := data[key]
	if !ok {
		return def
	}
	switch s := v.(type) {
	case string:
		switch strings.ToLower(strings.TrimSpace(s)) {
		case "1", "true", "on", "yes":
			return true
		case "0", "false", "off", "no", "":
			return false
		}
	case float64:
		return s != 0
	case bool:
		return s
	}
	return def
}

// buildSetupPage 初始化向导页面（简洁中文表单）。
func buildSetupPage(errMsg string) string {
	errBlock := ""
	if errMsg != "" {
		errBlock = `<div style="margin-bottom:12px;padding:10px 12px;border-radius:10px;background:#fef2f2;color:#b91c1c;font-size:13px">` + htmlEscape(errMsg) + `</div>`
	}
	return `<!doctype html>
<html lang="zh-CN">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>初始化 文件快传</title>
  <style>
    body{margin:0;min-height:100vh;display:grid;place-items:center;padding:16px;font-family:-apple-system,"Segoe UI",sans-serif;background:#f5f5f7;color:#18181b}
    main{width:min(100%,640px);padding:24px;border-radius:16px;background:#fff;box-shadow:0 18px 50px rgba(23,32,51,.08)}
    h1{margin:0 0 6px;font-size:20px} p{margin:0 0 16px;color:#71717a;font-size:13px}
    label{display:block;margin:10px 0 4px;font-size:12px;color:#3f3f46;font-weight:600}
    input{width:100%;height:36px;border:1px solid #e4e4e7;border-radius:8px;padding:0 10px;box-sizing:border-box;font:inherit}
    .grid{display:grid;grid-template-columns:1fr 1fr;gap:0 12px}
    button{width:100%;height:40px;margin-top:16px;border:0;border-radius:10px;background:#18181b;color:#fff;font:inherit;font-weight:700;cursor:pointer}
  </style>
</head>
<body><main>
  <h1>初始化 文件快传</h1>
  <p>首次配置管理员密码、上传限制和取件策略，后续可在后台调整。</p>
  ` + errBlock + `
  <form method="post" action="/setup" autocomplete="off">
    <label>站点名称</label>
    <input name="site_name" maxlength="80" placeholder="文件快传">
    <div class="grid">
      <div><label>管理员密码</label><input name="admin_password" type="password" minlength="8" required></div>
      <div><label>确认管理员密码</label><input name="confirm_password" type="password" minlength="8" required></div>
      <div><label>单文件大小限制</label><input name="upload_size_value" type="number" min="1" value="10" required></div>
      <div><label>大小单位</label><input name="upload_size_unit" value="MB" required></div>
      <div><label>上传频率（次/分钟）</label><input name="uploadCount" type="number" min="1" value="10" required></div>
      <div><label>上传检测窗口（分钟）</label><input name="uploadMinute" type="number" min="1" value="1" required></div>
      <div><label>取件错误频率（次/分钟）</label><input name="errorCount" type="number" min="1" value="10" required></div>
      <div><label>取件错误窗口（分钟）</label><input name="errorMinute" type="number" min="1" value="1" required></div>
      <div><label>登录失败频率（次/分钟）</label><input name="loginCount" type="number" min="1" value="5" required></div>
      <div><label>登录失败窗口（分钟）</label><input name="loginMinute" type="number" min="1" value="15" required></div>
      <div><label>最长保存时间</label><input name="save_time_value" type="number" min="0" value="0" required></div>
      <div><label>保存时间单位</label><input name="save_time_unit" value="day" required></div>
    </div>
    <label>允许文件类型（逗号分隔，* 不限制）</label>
    <input name="allowed_file_types" value="*">
    <label>提取码类型（number=数字 / secret=随机字符）</label>
    <input name="code_generate_type" value="secret">
    <label><input type="checkbox" name="openUpload" value="1" checked style="width:auto"> 允许游客上传</label>
    <label><input type="checkbox" name="enableChunk" value="1" style="width:auto"> 启用切片上传</label>
    <input type="hidden" name="expireStyle" value="day">
    <input type="hidden" name="expireStyle" value="hour">
    <input type="hidden" name="expireStyle" value="minute">
    <input type="hidden" name="expireStyle" value="forever">
    <input type="hidden" name="expireStyle" value="count">
    <button type="submit">完成初始化</button>
  </form>
</main></body></html>`
}

// buildSetupSuccessPage 初始化完成页。
func buildSetupSuccessPage() string {
	return `<!doctype html>
<html lang="zh-CN"><head><meta charset="utf-8"><meta http-equiv="refresh" content="2;url=/#/admin"><title>初始化完成</title></head>
<body style="display:grid;place-items:center;min-height:100vh;font-family:-apple-system,sans-serif;background:#f6f8fb;color:#172033">
<main style="text-align:center;padding:32px;background:#fff;border-radius:12px;box-shadow:0 18px 50px rgba(23,32,51,.08)">
<h1>初始化完成</h1><p>管理员密码已设置，请使用刚才的密码登录后台。</p><a href="/#/admin">进入后台</a>
</main></body></html>`
}

// htmlEscape HTML 转义（错误信息拼接用）。
func htmlEscape(s string) string {
	r := strings.NewReplacer("&", "&amp;", "<", "&lt;", ">", "&gt;", `"`, "&#39;")
	return r.Replace(s)
}